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Date:      Mon, 19 Nov 2007 11:57:23 +0800
From:      Dinesh Nair <dinesh@alphaque.com>
To:        Manolis Kiagias <sonicy@otenet.gr>
Cc:        Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>, freebsd-questions@freebsd.org
Subject:   Re: hyperthreading CPU and broken scheduling?
Message-ID:  <20071119115723.0701c02a@prophet.alphaque.com>
In-Reply-To: <4740140C.6050103@otenet.gr>
References:  <20071118111446.H4507@wojtek.tensor.gdynia.pl> <4740140C.6050103@otenet.gr>

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On Sun, 18 Nov 2007 12:29:32 +0200, Manolis Kiagias wrote:

> Wojciech Puchar wrote:
> > i have machune with intel's CPU with hyperthreading.
> >
> > it is detected right, but only first thread is ever used.
> >
> > top shows at least 50% idle no matter what i run!
> >
> > what's wrong?
> To enable hyperthreading, try setting the following in /etc/sysctl.conf:
> 
> machdep.hyperthreading_allowed=1
> 
> and reboot (or execute sysctl machdep.hyperthreading_allowed=1 by hand).

would an SMP kernel be required to properly use hyperthreading, or would
just the above sysctl setting be enough ?

-- 
Regards,                           /\_/\   "All dogs go to heaven."
dinesh@alphaque.com                (0 0)   http://www.openmalaysiablog.com/
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